Detective Jim Strovink, Clackamas County sheriff's spokesman, said that after receiving information about possible domestic abuse, the sheriff's office asked Portland police to investigate in April 2009.

"The sheriff insisted on having an independent investigation done by a neutral agency," Strovink said.

Portland police turned their findings over to the sheriff's office. The domestic-abuse investigation did not result in criminal charges and apparently did not trigger any disciplinary actions.

A police officer convicted of domestic abuse would be barred from possessing a firearm, making it impossible to continue working in law enforcement.

Strovink said the investigation was not announced earlier because state law prohibits police agencies from revealing investigations into police personnel unless they result in some kind of disciplinary action. He said Sheriff Craig Roberts planned to invoke an exception in the law, allowing for disclosure when there is an overriding "public interest."

"We will make all of that open to inspection as soon as Gresham police complete their investigation," Strovink said.

On the night of Feb. 12, Grahn, 46, walked into Gresham's M&M Restaurant & Lounge and confronted his wife, Charlotte, who was sitting with friends. Grahn and his wife went outside, where he fatally shot her. Moments later, police said, he re-entered and shot two of his wife's friends, then left and shot himself dead outside.

Charlotte M. "Char" Grahn, 47, of Boring and Kathleen "Katie" Hoffmeister, 53, of Gresham, both died of gunshot wounds to the head, autopsies say. Victoria "Vickie" Schulmerich, 53, of Gresham remained in critical condition Friday in the intensive-care unit at OHSU Hospital in Portland. A family friend said she was in a coma.

Jeffrey Grahn, a 15-year sheriff's office veteran, filed for divorce in August, but the petition was about to be dismissed for lack of legal action in the case. The couple continued to live together.